Benefits from visualization of environmental factor gradients: a case study in a protected area in central Russia

Introduction: Ecological scales include plant species, which are responsive to changes in habitat conditions. Such plants act as phytoindicators that integrate many environmental factors. Objective: To identify suitable habitats for searched-for plant species based on phytoindication data. Materials and methods: Altogether, 47 square plots (100 m2) were established within a selected forest area of the Mordovia State Nature Reserve. In each plot, species composition was recorded for further analysis, and the mean values of four environmental factors (shading, soil moisture, soil nitrogen, and soil pH) were calculated using the Tsyganov ecological scale. To visualize changes in factor values, contour maps were created for each factor. To reveal differences between species composition in study plots, Jaccard’s similarity index was calculated. Results and discussion: All study plots have been arranged mainly along gradients of three soil parameters, namely pH, nitrogen availability and moisture, while habitat shading has not acted as strongly. Gradient maps obtained of four selected environmental factors demonstrated remarkable similarity. This suggestion is confirmed by the distinguishing of three areas because of overlapping of these maps. Similarity between values of environmental factors and plant distribution was determined. The use of phytoindication methods allows showing changes in the values of environmental factors in a forest area, and being combined with a species similarity index, it is possible to predict habitat suitability for threatened plants. Conclusions: The possibility of indicating and finding an area suitable for inhabitation of plants based on the phytoindication ecological scale approach was determined. As threatened plants have a narrower range of environmental conditions, this method is especially suitable for these investigations.